Gymnosperms
Gymnosperms are the group of spermatophytes (seed plants) but, unlike angiosperms, their seeds are not contained within a fruit.
They were the first flowering plants, and although they appeared in the Paleozoic, their maximum development occurred in the Mesozoic.
The main characteristics of gymnosperms are:
- They usually resist cold and aridity well, so they can grow in very cold areas or in temperate and dry areas.
- Its leaves are usually perennial and small, needle-shaped (as in pines) or scaly (cypresses). In this way they prevent water loss .
- Its flowers are not showy, they have neither calyx nor corolla, they only have the reproductive parts, stamens if they are male flowers, or carpels if they are female, since they are unisexual flowers. In most, they are usually grouped in inflorescences or cones (male or female) or pineapples.
- Male cones : they are small in size, they produce pollen grains, which contain the male gametes.
- Female cones : they are pineapples, and contain female gametes that will give rise to seeds (pine nuts).
- Anemophilous pollination.
- The most abundant gymnosperms are conifers, such as pines, firs, cypresses, etc. Other examples of gymnosperms are yews, redwoods, junipers, ginkgos, etc.
- They are generally trees with large, woody stems, but they can also be shrubs.
